#include <inttypes.h>
#include <stdio.h>
#define LONGx1 "8192"
#define LONGx2 "16384"
void main(void) {
   const char *n = "abcdefghijklmnopqrstuvwxyz0123456789";
   uint64_t c0 = 0, c1 = 1, c2 = 2;
   uint64_t s;
   uint32_t eax = 1, ecx;
   __asm__("cpuid"
           : "=c"(ecx)
           : "a"(eax)
           : "%ebx", "%edx");
   __asm__("crc32b\t" "(%1), %0"
           : "=r"(c0)
           : "r"(n), "0"(c0));
   __asm__("crc32q\t" "(%3), %0\n\t"
           "crc32q\t" LONGx1 "(%3), %1\n\t"
           "crc32q\t" LONGx2 "(%3), %2"
           : "=r"(c0), "=r"(c1), "=r"(c2)
           : "r"(n), "0"(c0), "1"(c1), "2"(c2));
  s = c0 + c1 + c2;
  printf("avoiding unused code removal by printing %d, %d, %d\n", (int)s, (int)eax, (int)ecx);
}